Can be anything really that would make you want to vote someone, like a flip flop on a read, an early claim, or hammering at E-1 without allowing a claim. Really just wanting to see what others see as scummy, and take all of that into consideration for writing another guide. (Might be a while, but it's been on my mind, so thought I'd be a bit proactive).
If you'd like to check out my other guide, here's Playing As Mafia.